Looks like a city from overhead. Amazing.
There's a reason why "circuit as a city" used to be a common visual metaphor in pop culture when computers came up. E.g. this scene from the Hackers:
Casio-F-91W die-shot
111–120 of 167 posts
Re: Casio-F-91W die-shot
#112Earlier quoted context omitted.
At around 1976-1977 I bought one of those fancy new LED wristwatches, where you pressed a button and the time lit up in red. Straight out of James Bond, as I recall. As I was studying electronics at the time I brought the watch to the lab and opened it and connected a frequency counter to the oscillator, you could clearly see the crystal and a little trimming pot (I don't remember by now if that was a pot or somethin…
Get a Casio G-Shock. The 800 models can sync with your phone and the time is auto corrected. I bought a GBA-800 from a pawn broker - out of the dozen or so watches in my box it's the one I reach for if I have to know what time it is accurately.
Absolutely, get a G-Shock. But get one which radiosyncs. Most phones (and PCs), although synced by internet, reliably lag between one and two seconds.
My synced G-Shock is always correct to within better than one tenth of a second, that is, to the limit of observability. Solar powered, too, so it's just an utterly reliable black box. My favourite gadget by far.
Re: Casio-F-91W die-shot
#113Casio is an under leveraged brand. One of the few that could, I think, be taken into more product areas than it is currently. There's brand equity there they are not fully leveraging.
But why? Do we really want and need a Casio rice cooker? And since they're specialists in cheap and reliable watches (and calculators and few more things), what would happen to their brand if the rice cookers were shitty?
FWIW, they're also specialists in expensive and reliable ruggedized watches (G-Shock, especially the higher-end variants with compass, GPS etc).
Re: Casio-F-91W die-shot
#114Apologies for a silly question, what exactly are we looking at here? I've seen the inside of an F-91W, and I always imagined that under the black epoxy blob was some kind of off-the-shelf microprocessor (most likely 4-bit) with a mask ROM containing the watch's logic. Is the entire watch run from this IC, with no processor? If so that's really interesting.
If you are making millions of units for a RT application you definitely want custom silicon.
Is this on account of cost, or simplifying verification? I was under the impression that minimising the overall risk of a design was a major consideration. I'd love to know more about how these design decisions were made.
Re: Casio-F-91W die-shot
#115This is a remarkably interesting image. How do these guys even get these shots? I'd love to do this on all kinds of things at home..
Some time ago I posted exactly about that : https://zeptobars.com/en/read/how-to-open-microchip-asic-wha...
My latest microscope is this one, but Casio photo was made by temporary microscope I assembled from Thorlabs & Olympus parts: https://3.14.by/en/read/olympus-bx60-fluorescence-metallurgi...
Re: Casio-F-91W die-shot
#116Dumb question: is it legal to share a die shot like this one? What does copyright law say about this? I mean, yes, the author took the photo himself but what about the underlying material? Can I share a photo of an entire book? Do I own the copyright to a photo of a painting?
I don't think it is any different than taking a photo of your car engine or gearbox or any such component. Issues comes when you start to make copies.
Yep, this is my understanding.
Also, world practice shows that noone ever got into troubles for posting chip pictures, and in 10 years noone ever contacted me to remove any photos.
But companies do get intro troubles for trying to do copycat chip production, although it is not always easy to prosecute.
Re: Casio-F-91W die-shot
#117Re: Casio-F-91W die-shot
#118Earlier quoted context omitted.
If you are making millions of units for a RT application you definitely want custom silicon.
Is this on account of cost, or simplifying verification? I was under the impression that minimising the overall risk of a design was a major consideration. I'd love to know more about how these design decisions were made.
Power consumption and cost.
10 years on a battery is very hard to achieve for microcontroller.
https://sorwatch.net shows that : with much more advanced microcontroller (much more modern tech.node, low power features) - it only works for 1-2 years on a single battery after extensive power optimizations.
In custom silicon when seconds tick - it's maybe 100 transistors change their state. In microcontroller - it's roughly 10'000-100'000 transistors changing state to handle interrupt and update display content...
Re: Casio-F-91W die-shot
#119Earlier quoted context omitted.
For die photos, you want a metallurgical microscope, one that shines light down through the lens. A typical microscope shines the light from underneath, which works well for biological samples, but not so well for chips. The tricky part is decapping the chip. The easy way is to get a ceramic package, which you can decap with a chisel. Or a metal can, which you can open with a hacksaw. With a standard epoxy package, y…
Have you tried ImageJ, specifically the Grid/Collection Stitching? I use it for microscope stitching and it works pretty well.
I tried it at the beginning, but found it quite complicated.
A the moment Hugin is used, which works nearly perfectly, especially on XY stage where you can disable frame rotation optimization.
Re: Casio-F-91W die-shot
#120Does it run Doom?
Not... yet :-)